what type of questions are asked for a team leader role, plus any insight into strength questions

The questions depends of the role you are applying. For Team Leaders leadership will be the main topic. Therefore any examples of how you could manage and develop a team will help. You cannot prepare for strength based questions. You will be asked how you would deal with particular situations and your response has to show your thought process.

It would depend on the role, my advice would be to carefully read the essential criteria for the specific role applied for, and review the success profile specific to the grade of the role you are interested in. I have posted a link which can be accessed via gov.uk website: https://www.gov.uk/government/publications/success-profiles. The questions will be based around making effective decisions and leadership. Strength based questions assess your natural response to questions so it's best not to over think these questions, the interview panel will be looking for enthusiasm and your natural response.